全文获取类型
收费全文 | 12247篇 |
免费 | 902篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 135篇 |
儿科学 | 368篇 |
妇产科学 | 285篇 |
基础医学 | 1439篇 |
口腔科学 | 203篇 |
临床医学 | 1425篇 |
内科学 | 2609篇 |
皮肤病学 | 133篇 |
神经病学 | 1003篇 |
特种医学 | 589篇 |
外国民族医学 | 1篇 |
外科学 | 2043篇 |
综合类 | 129篇 |
一般理论 | 11篇 |
预防医学 | 1058篇 |
眼科学 | 214篇 |
药学 | 617篇 |
中国医学 | 11篇 |
肿瘤学 | 929篇 |
出版年
2023年 | 116篇 |
2022年 | 255篇 |
2021年 | 552篇 |
2020年 | 278篇 |
2019年 | 410篇 |
2018年 | 474篇 |
2017年 | 345篇 |
2016年 | 363篇 |
2015年 | 451篇 |
2014年 | 608篇 |
2013年 | 660篇 |
2012年 | 1036篇 |
2011年 | 1084篇 |
2010年 | 573篇 |
2009年 | 443篇 |
2008年 | 782篇 |
2007年 | 742篇 |
2006年 | 714篇 |
2005年 | 635篇 |
2004年 | 523篇 |
2003年 | 495篇 |
2002年 | 432篇 |
2001年 | 62篇 |
2000年 | 45篇 |
1999年 | 58篇 |
1998年 | 88篇 |
1997年 | 81篇 |
1996年 | 67篇 |
1995年 | 56篇 |
1994年 | 54篇 |
1993年 | 62篇 |
1992年 | 42篇 |
1991年 | 37篇 |
1990年 | 33篇 |
1989年 | 44篇 |
1988年 | 37篇 |
1987年 | 24篇 |
1986年 | 28篇 |
1985年 | 27篇 |
1984年 | 34篇 |
1983年 | 23篇 |
1982年 | 34篇 |
1981年 | 24篇 |
1980年 | 25篇 |
1978年 | 18篇 |
1977年 | 18篇 |
1976年 | 16篇 |
1975年 | 23篇 |
1974年 | 13篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
R E Dales A Mehdizadeh S D Aaron K L Vandemheen J Clinch 《The European respiratory journal》2006,28(2):319-322
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction. 相似文献
12.
Aaron H. Burstein Pharm.D. William G. Reiss Pharm.D. Eric Kantor B.A. Gail D. Anderson Ph.D. 《Pharmacotherapy》1998,18(6):1271-1276
Study Objective . To characterize cytochrome P450 (CYP) 3A4 activity in premenopausal and postmenopausal women by evaluating the urinary 6-β-hydroxycortisokcortisol ratio. Design . Prospective study. Subjects . Thirteen premenopausal and 13 postmenopausal women who were healthy and not receiving drugs known to affect CYP3A4 activity. Interventions . Beginning on day 2 of menses, premenopausal women collected first morning urine samples every other day for a complete menstrual cycle. Postmenopausal women collected first morning urine every other day for 28 days. Measurements and Main Results . Mean weekly 6-β-hydroxycortisol:cortisol ratios did not differ during the phase (week) of the menstrual cycle. Daily ratios did not differ in postmenopausal women. No difference between premenopausal and postmenopausal women was found on comparing overall median ratios. Conclusion . Cytochrome P450 3A4 activity as measured by 6-β-hydroxy cortisol:cortisol ratio did not differ by week of menstrual cycle, suggesting no menstrual cycle-related changes. Menopause does not appear to be associated with differences in CYP3A4 activity, compared with premenopause. 相似文献
13.
The effect of sodium fluoride on trabecular architecture. 总被引:1,自引:0,他引:1
The effect of sodium fluoride therapy on iliac trabecular bone has been studied in 15 patients with primary osteoporosis by comparing bone biopsies taken before and after two years of treatment. A marked increase in bone volume (43%) was observed, which was attributable to an increase in trabecular thickness (46%) rather than their number. Because the trabecular bone surface, the trabecular number, the bone volume/trabecular width ratio, and the trabecular terminus number do not change significantly after fluoride treatment, we conclude that fluoride does not induce the de novo generation of trabeculae, nor does it restore trabecular connectivity despite the restoration of bone mass. These data suggest that the restoration of skeletal mass with fluoride may not lead to a comparable decrease in the risk of future fracture. 相似文献
14.
Aaron M Kipp Jennifer A Lehman Richard A Bowen Patricia E Fox Michael R Stephens Kaci Klenk Nicholas Komar Michel L Bunning 《The American journal of tropical medicine and hygiene》2006,75(4):688-690
To better understand the potential environmental health risk presented by West Nile virus (WNV)-contaminated feces, we quantified the amount of WNV present in the feces of experimentally infected American crows (Corvus brachyrhynchos) and fish crows (Corvus ossifragus). Peak fecal titers ranged from 10(3.5) to 10(8.8) plaque-forming units (PFU)/g for 10 American crows and from 10(2.3) to 10(6.4) PFU/g for 10 fish crows. The presence of infectious WNV in bird feces indicates a potential for direct transmission of WNV. Thus, handlers of sick or dead birds should take appropriate precautions to avoid exposure to fecal material. 相似文献
15.
Roger S Chan Michael H Duong Aaron V Kaplan 《Catheterization and cardiovascular interventions》2007,70(3):374-378
Percutaneous intervention in saphenous vein grafts (SVG) carries a higher risk of distal embolization than intervention in a native vessel, and use of a distal protection device has been shown to improve the outcomes in SVG interventions. We describe an intervention done in an unexpected 'Y' SVG which required dual distal protection with Filterwires placed in both limbs of the diseased graft and which was performed via a 6 Fr guide catheter. 相似文献
16.
Ying-Ying Huang Aaron C.-H. Chen James D. Carroll Michael R. Hamblin 《Dose-response》2009,7(4):358-383
The use of low levels of visible or near infrared light for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing cell death and tissue damage has been known for over forty years since the invention of lasers. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial in mainstream medicine. The biochemical mechanisms underlying the positive effects are incompletely understood, and the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. A biphasic dose response has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light. The so-called Arndt-Schulz curve is frequently used to describe this biphasic dose response. This review will cover the molecular and cellular mechanisms in LLLT, and describe some of our recent results in vitro and in vivo that provide scientific explanations for this biphasic dose response. 相似文献
17.
Aaron Bonner-Jackson John G Csernansky Deanna M Barch 《Neuropsychopharmacology》2007,61(10):1141-1147
BACKGROUND: First-degree relatives of individuals with schizophrenia show cognitive impairments that are similar to but less severe than their ill relatives. We have shown that memory impairments can be improved and prefrontal cortical (PFC) activity increased in individuals with schizophrenia by providing beneficial encoding strategies. The current study used a similar paradigm to determine whether siblings of individuals with schizophrenia (SIBs) also show increases in brain activity when presented with beneficial encoding strategies. METHODS: Twenty-one SIBs and 38 siblings of healthy comparison subjects underwent functional magnetic resonance imaging scans while engaged in deep (abstract/concrete judgments) and shallow (orthographic judgments) encoding. Subjects were then given a recognition memory test. RESULTS: The groups did not differ on encoding or recognition accuracy, and the SIBs benefited from deep encoding to a similar degree as control subjects. The SIBs showed deep encoding-related activity in a number of PFC regions typically activated during semantic processing. However, SIBs showed more activity than control subjects in three subregions of PFC (left BA 44 & BA 47 bilaterally). CONCLUSIONS: Siblings of individuals with schizophrenia benefit from supportive verbal encoding conditions. Like individuals with schizophrenia, SIBs also show increased task-related activity in a larger number of PFC subregions than control subjects during deep verbal encoding. 相似文献
18.
M Rusli W H Spivey H Bonner R M McNamara C K Aaron C M Lathers 《Annals of emergency medicine》1987,16(3):314-318
We conducted a study to evaluate the absorption of endotracheally administered diazepam and the pulmonary pathologic changes induced by its administration. Six cats received diazepam and five cats received saline endotracheally. Serial blood gases and serum diazepam levels were drawn at intervals for 90 minutes after the administration of diazepam. The cats were sacrificed after two days and their lungs were examined by a pathologist. Mean diazepam levels reached a peak two minutes after the administration of diazepam and remained elevated above therapeutic levels for 90 minutes. There was no significant change in pH, PO2, or PCO2 for either group. Histologic examination of the lungs showed a significantly increased incidence of pneumonitis in the diazepam group as compared to the saline group. This study demonstrates that although diazepam is well absorbed when administered endotracheally, it has adverse effects on the lungs that may preclude endotracheal use in the currently available commercial form. 相似文献
19.
Hamid R Djalilian Saswata Roy Aaron G Benson Christopher Regala Timothy B McDonald Tina Leman 《Otology & neurotology》2005,26(4):674-677
OBJECTIVE: Given the associated risk of general anesthesia in elderly patients with cardiovascular disease, the authors set out to determine the feasibility of transcanal cochlear implantation under local anesthesia with monitored anesthesia care. METHODS: A 70-year-old man with a history of coronary artery bypass grafting, diabetes mellitus, and an American Society of Anesthesiologists Class III cardiac status underwent cochlear implantation under local with monitored anesthesia care. RESULT: With the described technique and regimen of intravenous remifentanil and dexmedetomidine, the patient tolerated the 60-minute procedure without tachycardia, hyper- or hypotension, or cardiac ischemia. CONCLUSION: Cochlear implantation using the pericanal electrode technique performed under local anesthesia with monitored anesthesia care is possible in patients at risk for undergoing general anesthesia for cochlear implantation. 相似文献
20.
Evelyn A Paysse Mohamed A W Hussein Aaron M Miller Kathryn M Brady McCreery David K Coats 《Journal of AAPOS》2007,11(4):388-392
OBJECTIVE: To compare structural and functional outcomes and efficiency of diode laser photocoagulation for retinopathy of prematurity (ROP) when delivered in a pulsed mode versus a near-continuous mode. METHODS: A retrospective study was conducted of 138 patients who underwent diode laser photocoagulation for threshold ROP using either pulsed or near-continuous delivery. Laser-related complications and structural and functional outcomes were analyzed. Prospectively, time efficiency and total energy used were evaluated in nine infants with bilateral symmetric high-risk prethreshold ROP in which one eye of each infant was randomized to pulsed and the fellow eye to near-continuous delivery. RESULTS: There was no significant difference between groups with regards to prevalence of posterior disease (Zone 1 or posterior Zone 2) (p = 0.11), postoperative vitreous haze (p = 0.60), postoperative complications (p = 0.38), retinal detachment (p = 0.90), strabismus (p = 0.73), amblyopia (p = 0.69), or refractive error (p = 0.95). Mean time for treatment was 23 minutes using pulsed delivery versus 14 minutes per eye with near-continuous delivery (p < 0.001). The mean total power used per eye with pulsed mode delivery was 1.5 x 10(5) W versus 1.1 x 10(5) W with near-continuous delivery (p = 0.015). CONCLUSIONS: No differences in complications, functional outcome, or structural outcome were found between using pulsed mode and near-continuous mode diode laser delivery for high-risk ROP. Near-continuous laser delivery, in our hands, was more time-efficient and used less total power. 相似文献